That is a good question. I noticed even at this early stage in the game that it feels more like an actual "you solve it" mystery. Where you are trying to gather facts, witnesses, info rather than open a multitude of locked doors.

is the game 100% linear (and by that I mean the game only proceds in one direction, you gather evidence until you finally get one name), or during the course of the game you actually investigate several suspects, and the game keeps you guessing about which one it might be?

Well locations are saved as pins on a map and you can go back at any time.

There are items to look at and in locales, not a ton of things to get or discuss - so doesn't seem like you would miss anything - but as with all games, it pays to scan an area closely and assume if you can go to a place, there must be something significant to find or look at there.

It must be fairly linear at least at the beginning as I have ben tripping along without feeling at all stuck or lacking a next step. I am just now getting hints at the larger plot, but still at the early discovery stage of the game.